Automatic telephone system



F. M. WARD, L. C. BYGRAVE AND H. J.'HER|NK.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED SEPT. I3. I912.

Patented NOV. 23, 1920.

4 SHEETS-SHEET l.

/ I 2 I gi. 2 5

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION HLED 85121213.1917.

4 SHEETS-SHEET 2.

Patented Nov. 23, 1920. s

F. M. WARD, L. C. BYGRAVE AND H. J. HERINK.

AUTOMATIC 'TELEPHONE SYSTEM.

AP'PLlcATloN FILED sEPT.13.191.

15359340, 'Patentd Nov. 23, 1920.

4 SHEETS-SHEET 3.

B 6a [Il A 20. l1. la. la 'fbi figa lF. M. WARD, L. C. BYGIIAI/E AND II. I. IIEIIINK.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED SEPT. I3. 1917.

Patented Nov. 23, 1920. 5 4 SHEETS-SHEET 4.

.l v u f f/ f 2 Q UNITED srarasl lement# ortica.,

FRANCIS MORLEY WARD, LEONARD CHARLES BYGDAVE, ANDA-HENRY JAMES HERINK, or LONDON, ENGLAND, AssIGNoRs To THE RELAY AUTOMATIC TELEPHONE poMPANY, LIMITED/F LONDON, ENGLAND.

AUTOMATIC TELEPHONE SYSTEM.

l'To all whom it may concern.'

IVARD, LEONARD CHARLES BYGRAvE, and

HENRY JAMES HERINK, subjects of the King of Great Britain, all residing at Marconi House, Strand, London, England, have invented new and useful Improvementsv in Automatic Telephone Systems, of which the following is a specification.

Our invention relates to automat-ic telephone systems and the automatic part of semi-automatic telephone systems in which apparatus common to groups of lines are used. In such systems groups of lines are used for connecting one line to one of a plurality of other lines and auxiliary apparatus is `common to the group. It is necessary. when the traffic is considerable, to give the calling lines access to or to make available a plurality of auxiliary apparatus and exclusively1 to associate one of such common apparatus with the calling line during the impulsing or connect-ing period and to render other common apparatus available to other potential calling lines.v

w In systems -in which impulse senders of the uncontrolled type have been employed.

and in which the impulse responders or the like are accessible to a plurality of lines. the time of engagement of such responder may be considerable owing to the tardy or faulty operation of an impulse sender. The object of this invention is to reduce this engaged time to a minimum by so arranging the responders that they are not engaged or exclusively associated with a'calling line until the sending of the impulses commences. and that they are disengaged at the end of the impulsing.

The invention is illustrated by its application to calling linesl having access to impulse respon ers which are then exclusively associated therewith and determine jwith which group of lines corresponding with the digit impulses set up by the caller a calling line is to be connected; butthe invention is not limited to such arrangements as it is also applicable to the picking up of anyone of a plurality of common apparatus, such as registers and the like'.

It is known that one of a plurality of common devices ,can be exclusively associated with a calling line by sending an impulse prior to the digit impulses but this.

*A Specification of Letters Patent. Patented No 23, 1920 Application tiled September 13, 1917; Serial No. 191,174. l

invention obviates the necessity of such an extra impulse and is applicable to a system using well known impulse sending devices on any system.

lccordingio this invention `when a subscilbfNs line is' extended vto atrunk line at a digit switching stage, asselector or impulse responder 1n a bypath ofthetrunk is tentatively associated with the trunk line and prepared to receive the impulses. If now the caller delays to send impulses and another caller in the same group removes his telephone to call, his extended line'will be sively associate the responder with his line while the other calling line will be tentatively associated wit-h another responder in another bypath. The firstl impulse of a digit thus exclusively associates one of a plurality of responders with the calling line and allows it to receive further impulses. The first impulse. although used primarilyvas described. is effective for calling digit No. 1

in combination with the normal contacts of the responder. and also as hereinafter described. Should only one impulse be i'equired to select the desired number. the responder goes through its cycle of operations and the wanted subscriber through the resting contact of the first responder relay or more positively as hereinafter described. after which the responder is released and becomes available for other calls.

By such an arrangement the responder relays are prepared in advapce so that a `minimum nlunber of relays has to operate between the first and second impulses. Oli the completionr of the digit impulses the im- `pulse responder and its bypath are auto- `matically disconnected from the trunk and are thereforeh free to be taken into engagement by another calling line.

Arrangements ai'e provided for insuring that` if all the responders associated with a group of lines are engaged and another calling line lis waiting. the retained responder relays are released before .the responderis re-prepared. 1

The invention is illustrated by the drawings in which Figure 1 shows the arrangement when two responders are provided for4 is marked v tion suitable for large systems in which the impulses are repeated at each stage; and Fig. 3 shows'a modification for use at a final stage requiring responders which respond to two series of impulses.

Figs. etl and 5 are diagrams showing -how the connecting apparatus may be arranged.

Fig. 1 shows one form of the invention whereby a lgroup of trunks has access to t-wo responders.I Only two trunks are shown (T 1 and T2) though any number could be connected to d, b. c, d, etc., a1, b1, c1, d1, etc., and p in' a similar mannerv to those shown; the six relays showlrin line with each trunk are individual to that trunk. JOnly one responder S1 is shown, the other S2 being an exact duplication and connected to al f1 .in a similar manner.

The subscriber is connected to the trunk by any suitable pre-selecting means in a known manner and the impulse relay 1E. operates when a subscribers line 1s extended Y to a trunk over circuit 1. Guarding relay 2E is operated over circuit 2. Circuit 3 is no w completed to prepare the responder. the slow release relay 3E energizing provided the responder is disengaged. This completes circuit -i and all the M relays operate.

The subscriber now operates his dial and breaks 1 Aa number of times equal to the value' of the digit to -be called. say, T 0n the first impulse 1E releases land 5E operates over 5 and holds over 6 for the duration of the impulse. TE now operates over T. t the end of the impulse '1E again operates and breaking 6 releases 5E. TE now holds over 8 and `operates 8E. The latter changes the line p over to the second responder by f to e1 and breaks line a so that if any calls are made while S1 is inuse, S2 will be.pre pared and used.

rl`he second lmpulse denergizes 1E and completing 9 operates A1, which locks over. 10.

M1 .now holdsover 11 (which follows the same path as 9 to 1E). `When 1E reenergizes 9 is broken and M1 releases. The

vthird impulse operates A2 over 12, M2 hold# ing over 13 (as in the case of 12 to 1E).

0n 1E renergizing M2 releases. rl`his breaks 10 and A1 releases thus re-*operating M1 over 4. y

A. similar-series of operations takes place for each impulsey.' the sixth impulse operating Aand releasing M5. 0n the seventh impulse 14 is completed and A1 again operates. This completes 15 and 15E is operated, locking over 15a. t the end of the impulse M1 releases, and this releases A5 and re-operates M5.

During the impulses ASElias beenmaintained by the impulses over the front contact of 8E. so that after the last vimpulse of a series has ceased it denergizes, 16 .is

i completed and apparatus associated with subscriber No. T, or the seventh group it it is a large system, is brought into action.

the speaking circuit is established. /lTE also breaks 8, releasing TE and 8E, and any responder relays that may be energized. lTE locks over la as long as the trunk is engaged. 'hen a selector isengaged the common circuit- T is opened at 8E so t-hat no other relay TEvcan energize.

On the subscriber clearing. 1E denergizes, and then 2E. releasing lTE when the trunk is ready for further calls.

The switch` P is providedin order that selector S2 may. if desired, be taken into use before S1. the lat-ter only being used when. S2 is engaged. This switch can be used to equalize the work over the selectors, and is also useful if S1 should become faulty.`

l*`ig.2 shows another ,form ofthe invention which is more suitable for the digitstages of a large system. It is usual in such systems to transmit the impulses from stage tostage over the and B speaking lines to operate the responder at the various stages, the impulses being given by completing the loop. A retaining wire is used to maintain the switches at each stage.

In the figure only two trunks are again shown (T1 and T2), the responders being connected to a, L. c, (I, al, b1, 01, Z1 and pin the sa'me manner as described for Fig. 1. The live relays in line with each trunk are individual to that trunk. i

When the call is extended to the stage under consideration, an earth is connected to the retaining wire, circuit 1 is completed and 11411 operates. rIbis earths p (circuit 2) and prepares the selector as already explained for Fig. 1. On the first impulse the lines AB are connected together and SE1 operates (circuit 3) locking over 4 to the retaining wire. This changes thevcircuit of 1E-1 to the A, line circuit 5, so that it only remains energized during the impulse. 'hen SE1 energized 6 was completed over responder Xo. 1, if free. and 'T over responder No. 2 if the former were engaged. In the former case v 6E is energized, locking over 8. At the end of the impulse :1E1 releases and the remain- D ,ing impulses operate the responderv` over 9 and' line d. When a selector is engaged, thecommon circuit 6 is opened in a manner similar to 7 in Fig. 1, so that no other relay .6E can energize; circuit T is therefore com- .-11 to the retaining wire in a. manner analogous -to 17E of Fig. 1. This breaks4 and releases SE1 and 6E and the responder is released, the AB and retaining Wiresbeing extended to the next switching stage in any y known manner. When the subscriber clears,

the retaining circuit'is broken and 10E! deenergizes. the trunk thus being free for further calls.

lt will be readily understood that either of the arrangements shown in F ig. 1 o1' Fig. 2 can be extended to give the trunks access to three or more responders.

Fig. 3 shows'another modification which is particularly suitable for the final stage where a two digit impulse responder is usually necessary. Only one trunk is shown and means for connecting to three responders is provided.` Only one responder is shown, .the other twol being similar and connected in an exactly similar manner to a1, b1, c1,

(Il, a2. b2. c2. (I2. The lines a., b. c, d. al.

b1. c1. (Il and the like can be multiplied to any number'of trunks. The circuit will be described Vfor a system in which the impulses are transmitted over the A and BV lines. as in Fig. 2. though it will be readily understood that in the case of a 10() line boardthe responder would be directly opel'- ated from the impulse relay asin Fig. 1. `vlien the call extended to the trunk lEX. operates off the retaining wire (circuit 1). This completes` 2 it' the first responder tree and 2li? and SEX. operate. It' S1 is engaged this circuit is broken by 12E and so 4 would be completed if S2 is.t'iee. operating E and the relay associated with S2.

ln a similar manner connection is established with responder S3 if bot-h Stand S2 are engaged. The operation ot' Sli' prepares the responder by opeiatiiig all the M relays (circuit 5).

circuit H and operating,.\1'. which locks over il. ()n the tirstv impulse the loop is com pleted over the and B wii'es and 10E* is operated (circuit 1E being maintained for the duration ot' the impulse over 11 (1 being broken by 10h11). 12 is completed holding up 10F.x and 2E while the selector 4.is in use and operating 12E. This latter changes Glix to the impulse wire ciiciiit Gu. so that it will release when the impulses cease. 12E also breaks line 7) so that no trunk can connect to the responder. At the end ot' the first impulse 1lix releases.

The second impulse operates A2 (circuit 13) M2 releasing at the end of the impulse. as explained t'or Fig. 1. The remaining impulses operate A3. A4 and the like. as bet'ore explained. 14E operating on the sixth impulse (circuit 14) and locking over 15. At the end ot' the series of impulses, 6E*

(SEK is' also operatedv (circuit (5) and Illl locks itself over T. Inl oi'der to lnake the operation of the responder u l l I a. deenerglzes, Say, after SIX. lmpulses have been sent. The negative (circuit T) is removed from 3E", which holds over 16, (circuit 7 vas previously a short circuit on relay 16E and prevented it` operating) 'operating 16E (as A1 isy the only A relay retained energized). On 16E operating, 9 is broken and A1 is released, renergizing M1. When A1 releases, 16 is broken and 3Ex releases, 16E holding over 17. 6Ex is renergized over 18.

The first impulse of the second series operates A1 over 19, and this retains over circuit 20 operatingQOE. The latter changes GEX to the impulse wire over and 6a. The relays A2, A3 and the like operate in turn as before. 21E operating on the sixth impulse (circi1it 21) and locking over 2Q. At

the end of the impulses GEX. releases and completes 23 operating 23E. In order to prevent two responders marking out at the same time '23E is double wound. the second winding being normally connected to a test wire T. This wire is connected in a similar manner to each responder and if any responder is marking 4out (that is. has its 23E relayenergized) negative` is connected to T. This'prevents the 23E relay ot' any other responder'energizing as current flows through both windings. and these neutralize one an other. 'hen 23E operates. the initially eny ergizing tens and units circuits Q4; and 25 are completed and by means ot' a marker (see British `specitication No. 4819. of 1914) or other" apparatus connection between the trunkvline and the wanted subscriber is established. At the sametime 26E is operated over 26. locking over 2T. T his releases 10E/ ICE 12E and all the responder relays. so that the responder is free to receive inipulses. Atrom vother trunks.

' With the circuit arrangement shown in Fig. I-l the responders themselves have no definite order of precedence. the responders to which aline has access and their order ot' precedence being determined b y the connecting apparatus associated with the line. lt is therefore possible to give different lines access to different responders and also to the .same responder. or to give different lines precedence to different responders.

For example. Fig. J. ot' the drawing illustrates oiie method ot' arranging the connecting' apparatus. The lines are shown divided 'into six sub-groups n1 to f1 which may eaclicoiisist of a plurality ot' lines. though only one is shown. Each line can obtain llO access to three responders. the slib-group a1 having access to responders l. Je and 6. in the order named. ly such an arrangement an efficiency. nearly equal to that when each line has access to all responders. is obtained, though the connecting apparatus is greatly reduced.

Fig. 5 illustrates by way of example one arrangement whereby different lines, or subgroups of line-s (al, bland c1) give precedence to different responders. For instance. the line al will use responder 2 if all responders be disengaged, whereas b1 would use 3 and@ would use y1. 4Line a1 -would only use 3 if 2 were engaged and 1 if both 2 and `3 were engaged. 4In this way the work is equally distributed over the responders.

f' Ye do not limit the application of the inv yention to full automatic systems, as it can 4be applied to semi-automatic systems,"for

impulse is sent and to be numericallyv effective.

` 2. In al telephone system, the combination of a number of subscriberslines, an impulse `sender for each line, a number of trunks accessible in ,common to each subscribers line, a .number of by-paths smaller than the number of trunks, numerical impulse responders in the by-paths, means `Whereby on a line being extended to a trunk a by-path is tentatively connected to a trunk, means whereby the first digit inipulse coming in over a subscr1ber`s llne and a trunk associates the responder with that trunk to the exclusion of other trunks and means whereby on the completion of the digit impulses the by-path and responder are disconnected from the trunk.

3. In a telephone system, the combination of a number of subscribers lines, a plurality of numerical impulse responders each of y which is accessible in common to a plurality of the lines, means for exclusively associating a responder wlth a line, means whereby, on another line being taken into engagement, a second responder is prepared, and

means whereby, should the first responder be released before the other responder is exclusively associated with the second line, the first responder is re-preparetL andfthe second responder is returned to normal. i

4. In a telephone system, the combination of a number of subscribers lines, a numerical impulse responder accessible in common to a plurality of the lines', means whereby, on one of the lines being taken into engagement, the impulse responder is connected to that line, and means for breaking the connection on the respnder being taken into engagement by another line before being taken into engagement by the first line.

5. In a telephone system, the combination of a number of subscribers lines, a plurality of numericalimpulse responders each of which is accessible in common to a plurality of the lines, means whereby, on one of the lines being taken intoV engagement. one of the impulse responders is connected to that line. means whereby a second line can take said responder into engagement, means for lbreaking the connection between the first line and said responder and means for con-v,

necting the first line to al second responder.

6. In a telephone system. the combination of a number of subscribers lines, an impulse sender foreach line, a numerical limpulse responder accessible in. common to a plural' ity of the lines, means wherebythe first impulse is caused to associate the responder exclusively with the line over which the impulse is sent, and a slow acting` relay forming part of the responder and dependent on the first and all succeeding impulses.

T. In a telephone system in which a responder is notnormally associated with a line, the combination of a number of lines, a plurality of numerical impulse responders actuated directly by the subscribers dial impulses each of which is' accessible in comfmon to a plurality of the lin'es for the purpose of setting up but not maintaining a connection. a distributing field .between the lines and the responders and means for associating a responder exclusively with a calling line.`

FRANCS MORLEY WARD. LENARD CHARLES BYGRAVE. uraar'mus Hemus. 

